1. Technical Field
This invention relates to a drop detection device. In particular, it relates to a device for use in relation to a product or package that has a fragility requirement that needs to be monitored. Still more particularly, the device detects whether the product or package has been dropped or impacted by another object.
2. Description of the Related Art
Certain materials and devices can be damaged if dropped. For example, dropping or hitting a hard disk drive with sufficient force can result in components of the hard disk drive being damaged. However, the damage may not be evident, either by looking at the exterior case of the hard drive, or even by opening up the case and physically examining the drive's components. Nonetheless, when put into operation, the drive may not function properly due to being dropped. That is, the external shock can cause a disk within the disk drive to slip resulting in inaccurate data recording or increased access times.
To detect whether a device or material has been dropped, different devices have been developed in the past. For example, acceleration limit switches are known in which a spherical inertia body made of ferromagnetic material is maintained in a resting position by a permanent magnet. On the opposite side of the spherical body to the magnet a flexible conducting diaphragm is disposed beyond which is a printed circuit board. If the spherical body is accelerated away from the permanent magnet, it will impact the diaphragm, which is flexible, and the diaphragm will deform to contact an element on the printed circuit board causing some form of signal to be activated.
Acceleration limit switches of this type have the disadvantage that they are only sensitive to acceleration in a single direction. Other forms of drop detection device may include fragile destructive assemblies or high technology accelerometers.
What is needed, therefore, is a multi-directional drop detector that is able to detect and provide an indication signal of a drop event that has been inflicted on a hard disk drive or other impact sensitive equipment or material.